Diabetes in Dogs - Insulin

Dr. Michael Richards

Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...

Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...

Q: Dr. Mike I am writing in reference to my Husky who is 12 yrs. old. She has diabete's and has been on inslin since Aug. 1996. She receives 40 units twice a day, I talk to Eli Lilly about the increase and they said this also happens with people where you have to keep increasing the dose. She started out with 20 units a day. Her sugar has never come under control. The curves we do about every 20 days now and the lowest it has been is 305. She eats Purina OM and vegtables as treats. She is feed two meals a day . The question I have is that her hair has become so thick and she has non stop shedding, The insulin is Humilin L. She is now blind in one eye the other seems ok. She does not act sick nor does she seem to tirer from play. I do not understand about the hair. I talked some with the Lilly Co. but they will only give info to vets or doctors, mybe you can find out some info on this. Sorry if typing is bad - new key board and it is black and I am having a hard time with this. Shamu is not over weight she weighs 57 lbs she looks real good and her skin is in great shape. She has never had fleas or worms or anything until this. My vet who I am moving away from in 2 weeks does not know anything about the drugs. I hope you can help and I will pass it along to him.

A: Joyce- Diabetes is difficult to control in many dogs. It may help a great deal if you split up the meals more -- giving four evenly spaced meals can help a lot with insulin regulation. It is important to interpret the glucose curves and try to figure out what the administered insulin is doing. In a case in which the insulin does not appear to be working effectively, several things have to be considered.

The first thing is handling and administration of the insulin itself. The questions you have to ask yourself are:

Is the insulin in date?

Am I mixing it gently?

Insulin should not be roughly shaken, very gently mixing the insulin or rolling the bottle between your palms is sufficient to mix it up.

Has the insulin changed in appearance?

Cloudiness can be a sign of deterioration in some insulin.

Am I successfully administering the injections?

Some dogs are hard to inject with insulin. In other cases, scar tissue or irritation may develop if one specific spot is used over and over again. It can help to keep injections in the same general area, though -- absorbency can be different from different areas of the skin.

Am I using an insulin product my dog has developed antibodies to?

Dog's immune systems can recognize the insulin used as a foreign invader and learn to destroy it. Changing types of insulin can help if this sort of reaction occurs.

The next group of things to think of are other health problems that may be complicating the use of insulin.

Does my dog have Cushing's disease (hyperadrenocorticism) as well as diabetes?

There are a number of medications which can interfere with insulin administration (complicate dosing it, at least). They include prednisone, other corticosteroids, Oviban (Rx) and other progesterone compounds, furosemide (Lasix Rx) and thiazide diuretics. Thyroid hormone may also have this effect.

While it isn't a big concern in your dog, anabolic steroids such as Winstrol V (Rx), propanolol, phenylbutazone (Butazolidin Rx), tetracyclines, aspirin and some other drugs may potentiate insulin. This can also make dosing difficult in some dogs.

What do you do if there do not appear to be complicating factors in the use of insulin, from medications or from concurrent illness in your dog?

In these cases it can help to change the type of insulin, anyway. In some cases, it is necessary to mix two types of insulin in order to get benefits that two types offer (such as a shorter term higher effect insulin with a longer lasting one). Most of the time when diabetes is this complicated it helps a great deal to consult with an internal medicine specialist who has experience with this sort of complication. Your vet can refer you to a specialist in your area of the country.

Whew!

Mike Richards, DVM

Regulating insulin

Q: Our dog has diabetes and is on insulin. Do we need to have blood tests to measure glucose values or will the urine testing be ok?

A: Jim- While we recommend blood testing for glucose values whenever possible, it is not always feasible for every client. This is what I know about urine glucose monitoring, in case it helps.

Urine glucose monitoring is not adequate, alone, for regulating insulin, in the opinion of most of the endocrinologists I have spoken with or whose information I have read. The problem with it is that you only really know if the glucose level is negative, slightly positive or strongly positive.

Negative may indicate good control or it may indicate that the insulin dosage causes hypoglycemia part of the day and you are measuring the glucose during that time (most commonly this would happen with twice daily measurements, for the evening sample).

Slightly positive results in the morning urine when insulin is given once a day is the ideal that everyone is looking for. It indicates that control of the diabetes is probably pretty good. Slightly positive results in the afternoon/evening urine sample when taking samples twice a day could indicate reasonable control or may indicate the need to slightly increase insulin dosage since this would be a little early for the insulin effect to be gone.

Strongly positive results in the morning urine glucose test can indicate that the insulin dose is inadequate or that it is excessive. If the glucose is not controlled at all, then the insulin dose is too low. In this case, an afternoon/evening sample should also show slight to strongly positive. If the insulin level is too high, the blood sugar drops to hypoglycemic levels during the day and the rebounds to very high levels in the morning. In this case, an afternoon/evening sample is likely to show a negative urine glucose level or a slight positive level.

It is much more accurate to use blood glucose curves to evaluate insulin needs since a graph of the glucose levels gives a pretty good picture of what is happening. This is especially good for detecting hypoglycemia/rebound reactions to insulin dosage.

One common mistake with insulin regulation is too frequently changing the insulin dose -- "chasing the glucose level". It takes a little time for the body to adjust to insulin dosage changes and for beneficial effects to be measurable. It is best to change the level and then leave it alone for two or three days before changing it again, when that is possible. Sometimes, in early regulation of insulin levels it isn't possible to be that patient as glucose levels skyrocket or hypoglycemia occurs.

Sometimes insulin loses some effectiveness due to inappropriate handling. Insulin should not be shaken, even though that is very tempting. The bottle should be gently rolled between the palms until the insulin is mixed in solution well again. The site of the insulin injection may need to be changed in order to allow consistent absorption. Usually it is pretty consistent if given on the sides of the trunk somewhere. Changing sites daily is a good idea (at least a little).

Many dogs require twice daily insulin dosages (I can't remember if you are doing this) to regulate diabetes. Some dogs need twice daily dosing and mixtures of different types of insulin. Usually when things get this complicated we refer our cases to a internal medicine specialist or veterinary school.

Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...